Apparatus for setting liners in boreholes of wells



Dec. 30 19 w. A. MAXWELL APPARATUS FOR SETTING LINERS IN BOREHOLES OF WELLS Filed Aug. 5, 1968 w 4 2 2, 2 O l 9 8 2 3 2 2 v k. w s R 2 9 2. 3 2 2 2 1. L

FIGUVREQZ I v INVENTOR.

WILBER A. MAXWELL FIGURE ATTORNEY United States Patent O 3,486,558 APPARATUS FOR SETTING LINERS IN BORE- HOLES F WELLS Wilber A. Maxwell, Box 138, Friendswood, Tex. 77546 Filed Aug. 5, 1968, Ser. No. 750,196 Int. Cl. E21b 33/ 132, 43/08 U.S. Cl. 166-165 ABSTRACT OF THE DISCLOSURE An apparatus for concurrently removing accumulated sand from a borehole and setting a screen liner comprising a perforated cylindrical liner and a wash pipe coaxially aligned therein, said wash pipe having valves adjacent its upper and lower ends adapted to permit flow upward through said wash pipe but prevent downward flow therethrough, a sand receiving load tubing string above said wash pipe and in communication therewith, a hydrostatic valve responsive to the upward force resulting from weighted contact of the lower end of the apparatus with the sand in the borehole, the apparatus being provided with a dry string of tubing above and in communication with said hydrostatic valve and means for downhole detachment of said liner.

6 Claims BACKGROUND OF THE INVENTION The present invention relates to the setting of a liner in the borehole of a well. More particularly, the present invention relates to an apparatus for setting a screen liner in a borehole containing an accumulation of sand in the bottom thereof with a single trip into the borehole for positioning the screen liner at the desired depth.

A frequently encountered difficulty in oil and gas wells is the accumulation of sand in the lower end of the borehole as a result of the migration of sand from the surrounding subterranean formations into the borehole. The sand may plug production tubing and as a result, may significantly reduce or in some instances, completely stop the production of fluids from the Well. Additionally, the sand passing through the downhole producing apparatus and the tubing may seriously erode such equipment thereby causing short life and early failure of such equipment. In many instances, the producing sands are so friable that sand can be washed from the lower end of the borehole and in the time it takes to make a round trip to install production tubing, the sand will accumulate to such extent as to again present a problem.

A common means of combating the sanding of boreholes is the installation of slotted or perforated liners in the borehole within the area of the casing perforations. Coarse sand or gravel is then packed around this liner. By so using the gravel packed liner, the plugging of the downhole producing equipment with sand and the erosion of such apparatus and the tubing by sand is either stopped completely or significantly reduced.

In the past, the setting of the liner has generally involved several trips with a sand bailer to remove the accumulated sand followed by removing the sand bailer and running in a tubing string with the liner on the lower end thereof. Therefore, to install the liner, it generally was required to make several trips into the borehole. Additionally, and particularly troublesome was the occurrence noted above wherein significant sand accumulated in the borehold between the time of the last trip with the sand bailer and the running downhole of the liner.

-It is an object of the present invention to provide a new and novel apparatus for setting liners in the boreholes of oil and gas wells. Another object of the present invention is to provide a new and novel apparatus for setting liners Patented Dec. 30, 1969 in boreholes of oil and gas Wells whereby the borehole may be cleansed of accumulated sand concurrently with the setting of the liner. Still another object of the present invention is to provide a new and novel apparatus for setting liners in boreholes of oil and gas wells and concurrently removing accumulated sand from said boreholes which alleviates the need of pumping fluid down through the tubing to Wash the sand from the borehole. A remaining object of the present invention is to provide a new and novel apparatus for setting liners in boreholes of oil and gas wells and concurrently removing accumulated sand from said boreholes which apparatus is particularly adapted for use in boreholes which have an accumulation of water in the casing above the producing formation. Additional objects will become apparent from the following description of the invention herein disclosed.

SUMMARY OF THE INVENTION The present invention, which fulfills these and other objects, is in one of its embodiments an apparatus which comprises (1) a perforated cylindrical liner having an end wall at the lower end thereof, said wall having an opening substantially at the center thereof, (2) a wash pipe coaxially aligned with said liner and extending down ward into sealed contact with the periphery of said opening in said end wall whereby fluid passing through said opening may pass into said washpipe, (3) a check valve within said wash pipe adjacent to the lower end thereof, said check valve adapted to permit flow into the lower end of said wash pipe from below and prevent downward flow from said wash pipe, (4) a second check valve above said wash pipe and connected thereto, said second check valve adapted to permit flow upward through said valve and prevent downward flow through said valve, (5) an intermediate tubing string or load tubing string comprised of a plurality of tubing joints sutficient to retain the sand to be removed from the bore hole, (6) a hydrostatic valve above said load tubing string and in communication therewith, said hydrostatic valve responsive to the upward force resulting from weighted contact of the lower end of said apparatus with the sand accumulated in the borehole, (7) a dry string of tubing connected to said hydrostatic valve and extending thereabove substantially to the surface of the earth and, (8) means for downhole detachment of said liner from the remainder of said apparatus.

Through use of the above described apparatus, a borehole may be concurrently cleansed of accumulated sand and a liner screen set therein for packing around with gravel or coarse sand to prevent future plugging and/oi failure of equipment as a result of sand accumulation in the borehole. The concurrent removal of such sand and positioning of the liner screen is generally carried out in a single trip of the tubing string into the borehole.

DESCRIPTION OF THE DRAWINGS FIGURE 1 of the drawings is a sectional view of the apparatus of the present invention as it is employed ir concurrently removing accumulated sand from the bore hole and seting the liner at the desired depth.

FIGURE 2 of the drawings is a sectional view of a hydrostatic valve suitable for use in the apparatus of th present invention.

tions 12 through which fluids may flow from formation 11 into the well borehole. Although the present invention is illustrated in a well in which casing is set through the production formation 11, its use is not limited to such installations and can be used when production is through an open borehole. It is usually desirable to set casing completely through the various formations, however, but in some instances casing may be set only to a formation above the producing formation.

Extending down through casing is a tubing string 13. This tubing string is a dry string which is to say that it contains no significant liquid therein. The tubing is of a diameter smaller than the diameter of casing 10 to thereby provide an annular space 14 between the tubing string 13 and casing 10 through which the gravel to be packed around the liner is passed.

Connected to the lower end of dry tubing string 13 is a hydrostatic valve section 15 in which the hydrostatic valve is located. While any of several hydrostatic valve constructions may be employed in the apparatus of the present invention, a particularly useful such valve is illustrated in the drawings, particularly in FIGURE 2.

Referring to the drawings and particularly to FIGURE 2 in which the hydrostatic valve is shown in closed position, the valve section is comprised of an upper body 16 and a lower body 17. Upper body 16 has an external sleeve portion 18 which terminates at its lower end in inwardly extending shoulders 19. For operation within external sleeve portion 18, lower body 17 has an internal sleeve portion which adjacent its upper end 21 extends outwardly to form shoulder stops 22. As may be seen from FIGURE 2, in extended position, shoulder stops 22 rest on the upper surface of shoulders 19 of external sleeve portion 18 thereby preventing disengagement of internal sleeve portion 20 from external sleeve portion 18. A tension producing means 23, preferably a coiled heavy duty spring, is located within external sleeve portion 18 to exert force against the upper end 21 of internal sleeve portion 20 to thereby force shoulder stops 22 of internal sleeve portion 20 against the upper surface of shoulders 19 of external sleeve portion 18. A tubular section 24 extends from the upper portion of upper body 16 through the upper end 21 of lower body 17 and into channel 25 within internal sleeve portion 20 of lower body 17. The outer surfaces of tubular section 24 are in slidable contact with the inner surfaces of channel 25. The slidable contact of the walls of channel 25 with tubular section usually is through a sealing medium which will prevent flow of liquids between the outer surface of the tubular section 24 and the internal surface of channel 25.

Lower body 17 has upper chamber 26 in open communication with flow passage 27. Within flow passage 27, a coiled spring 28 is located in such manner as to exert upward force against valve member 29 to thereby push valve member 29 into firm contact with the upper surface of chamber 26 surrounding channel 25. Attached to the upper surface of valve member 29 and extending upwardly into channel 25 is valve passage member 30 having slotted openings 31 in the sides thereof.

In operation, as the tubing string and associated equipment is rested on the bottom of the borehole, the weight of tubing above the hydrostatic valve forces upper body 16 downward. Thereby, external sleeve portion 18 is extended down and over inner sleeve portion 20 of lower body 17. Also, tubular section 24 passes downwardly through channel 25 and into contact with the upper end of valve passage member 30 thereby pushing valve passage member 30 and valve member 29 downward. Thereby, valve member 29 is forced away from the upper surface of chamber 26 and valve passage member 30 is extended down into chamber 26 a distance sufficient for slotted openings 31 to be completely within chamber 26. Fluids coming upward through flow passage 27 into chamber 26 then flow through slotted openings 31 and into 4 tubular section 24 and on up into the dry tubing string 13. To close the hydrostatic valve, it is only necessary to raise the tubing string enough to allow upper and lower bodies 16 and 17, respectively, to again extend their fullest distance from one another.

Below the hydrostatic valve section 15, is located load tubing string 32. The sand to be bailed from the borehole is introduced into and retained in this section of tubing. The length of the load tubing string will vary depending upon the amount of sand which it is anticipated must be raised from the borehole.

In order to remove excess fluid from load tubing string 32, it is often desirable to provide a means for draining the fluid from the tubing string. Such rneans generally comprises a drain sub section 33 located at the top of load tubing string 32 but below hydrostatic valve section 15. In a particularly useful embodiment, drain sub section 33 comprises a passage 34 surrounded by a tension producing spring 35. A chamber 36 is provided at the upper end of passage 34, this chamber usually having the upper side thereof formed by the lower end of hydrostatic valve section 15. As is shown in the drawings, chamber 36 is of a diameter such that fluid may be drained from such chamber by drain ports 37 downward and outside of passage 34. A closure disc 38 is provided to close on drain ports 37 and be held in such position by the expansion of tension producing springs 35. As pressure within chamber 36 increases, closure disc 38 is forced downward thereby permitting fiuid to be forced from chamber 36 through drainports 37.

The lower end of load tubing string 32 is provided with a check valve section 39 which prevents outflow from the bottom of load tubing string 32 and permits inflow through such bottom. While check valve section 39' may employ any of the usual arrangements for check valves, it is somewhat preferred to use the ball and seat arrangement shown in FIGURE 1. In this arrangement, the check valve includes a tapered passageway 40 and a spherical ball 41 of a diameter greater than the smaller end of tapered passageway 40. The tapered passageway 40 of check valve section 39 is arranged, as shown, with the small end down and the large end up. In this manner, if force is applied from below check valve section 39, ball 41 is forced away from its seating on the internal surface of the tapered passageway 40 thereby permitting a flow of fluid around the ball. When greater force is applied from above, however, ball 41 is forced downward into contact with such internal surfaces of tapered passageway 40 thereby closing flow through the valve.

For convenience in putting together the apparatus of the present invention, it is sometimes desirable to include a single joint of tubing pipe below check valve section 39. However, such a joint of tubing is not required and is merely an optional arrangement of the apparatus of the present invention.

Connected to check valve section 39 or to the joint of tubing therebelow, if such is provided, is washpipe 42 which is of reduced diameter, the diameter being less than that of the tubing above. This washpipe 42 extends downwardly into sealed contact with the periphery of the opening 43 in the lower end 44 of perforated liner 45. The sealed contact of washpipe 42 with the periphery of opening 43 is such as to permit fluids passing through opening 43 to enter washpipe 42 without leakage into the annular space between washpipe 42 and liner 45. In FIGURE 1 of the drawings, liner 45 is illustrated extending downward within accumulated sand 46. Stabilizing bars 47 are attached to the outer surface of liner 45 and extend into contact with the inner surface of casing 10 to thereby position liner 45 within casing 10.

The particular type of liner used in the apparatus of the present invention may vary considerably depending upon the choice of the user.The liner may range from a porous ceramic type material to two or more coaxially aligned concentric layers of a screen wire mesh or a slotted material. In addition, the liner may merely be a portion of cylindrical pipe containing numerous perforations therein. The choice of the best liner to use in a particular situation is well within the ability of those skilled in the art and is believed to require no further definition or description herein.

The lower end of washpipe 42 is provided with a check valve which permits entry of fluids from below into such lower end of the washpipe but which prevents the downward exit of such fluids once inside the washpipe. As mentioned above, the particular type of check valve used may include any of those conventionally employed in piping arrangements. However, as shown in the drawings, it is somewhat preferred that the check valve comprise a hinged lid 48 which is hinged to the lower end of washpipe 42 such as to swing inward into such lower washpipe section. Hinged lid 48 is responsive to pressure from below and if the pressure above hinged lid 48 becomes greater than that below, hinged lid 48 will be forced into a closed position thereby preventing downward exit of fluid from the washpipe.

In many instances, it is desirable to provide liner 45 with a push down shoe 49 which is attached to the lower end 44 of liner 45. Push down shoe 49 generally is cylindrical with the plane in which the lower edge 50 lies being at an angle other than 90 degrees to the axis of the cylindrical body of the pushdown shoe. The purpose of the push down shoe 49 is to provide a shaped lower tip for liner 45 to thereby aid in pushing liner 45 down into the accumulated sand. Additionally, by providing the angular arrangement of the plane of the lower edge 50 to the axis of the cylinder body of push shoe 49, fluid flow into the push shoe and up through hinged lid 48 is facilitated. Should the tip of push shoe 49 come in contact with or rest upon a substantially unmoving bottom, fluid may still flow through the open end of the push down shoe 49.

In order to remove the sand from the borehole while leaving the liner 45 in place downhole, it is necessary to provided a means for detaching liner 45 from the remainder of the apparatus of the present invention while such apparatus is still in the borehole. While many means for accomplishing such detachment are available and. readily apparent to those skilled in the art, a useful arrangement is illustrated in FIGURE 1. In this arrangement, at backoff section 51 is threaded onto the upper end of liner 45 and threaded joint 52. The threading between backoif section 51 and liner 45 is reversed to the direction of threading of the remainder of the threaded joints in the apparatus. Backolf section 51 is engaged with washpipe 42 such that the reverse rotation of the tubing string will also result in reverse rotation of backoif section 51 thereby causing the unscrewing of backoif section 51 from liner 45. The aforementioned sealed contact of washpipe 42 with the periphery of opening 43 of lower end 44 of liner 45 is of such nature that the pulling apart of washpipe 42 and lower end 44 will result in breaking of the seal and separation of the lower end of washpipe 42 from lower end 44.

In operation, the above described apparatus including dry tubing string 13 is run into a bore hole containing a standing column of fluid which preferably is at least 500 feet in height. The hydrostatic valve within hydrostatic valve section 15 is in closed position as the apparatus is run into the -bore hole. Closure of the hydrostatic valve results in the entrapment of air in the load tubing string 32 and the washpipe 42. This entrapped air substantally keeps fluid from entering load tubing 32 and the washpipe 42 as they are run downward through the fluid head.

On contact with the accumulated sand 46, the weight of the tubing string 13 forces push shoe 49 downward into the sand until the resistance otfered by such sand is sufiicient to substantially stop downward movement thereof. Such resistance offered against the weight of tubing string 13 results in the opening of the hydrostatic valve in hydrostatic valve section 15. The sudden opening of the hydrostatic valve allows the air entrapped in the load tubing string 32 and the washpipe 42 to escape upward. This creates a substantially lower pressure within load tubing string 32 and the washpipe 42 than that of the fluid column surrounding such equipment. As a result, hinged lid 48 of washpipe 42 is opened thereby permitting fluid to flow into the wash pipe and up through check valve section 39 into the load tubing string 32. This fluid flow sweeps much more of the accumulated sand 46 into the washpipe and on up into the load tubing string 32. To aid in completely loading the load tubing string 32 with sand it is often desirable to have the operator raised and then drop the tubing string against the accumulated sand 46.

To prevent excess pressure build up below the hydrostatic valve, the above mentioned drain sub section 33 is positioned immediately below the hydrostatic valve. Drain sub section 33 permits the fluid head above the loaded sand within load tubing string 32 to be drained therefrom.

Once the bore hole has been cleansed of the accumulated sand 46 to the desired degree and such sand is loaded into load tubing string 32, the tubing string is rotated in a direction counter to the direction of rotation normal for joining the various sections of tubing and the equipment of the present apparatus associated therewith. Such counter rotation results in the backing off of backoff section 51 from the upper end of liner 45. Once the backoif section 51 and the liner 45 are disconnected, the tubing string is pulled from the bore hole. The weight of the sand retained in load tubing string 32 maintains the check valve within check valve section 39 in closed position. The weight of t e sand in washpipe 42 maintains hinged lid 38 in closed position thereby retaining the sand entrapped within washpipe 42. I

The packing of the gravel around the liner 45 may be carried out by conventional means when the liner has been positioned at the desired depth.

Operation of the above described apparatus in the manner discussed above has led to the successful seating of liners on bore hole bottoms while removing from 70 to feet of sand from within the casing.

What is claimed is:

1. An apparatus for use in a well comprised of (l) a perforated cylindrical liner having an end wall at the lower end thereof, said wall having an opening substantially at the center thereof, (2) a washpipe coaxially aligned with said liner and extending downward in sealed contact with the periphery of said opening in said end wall whereby fluid passing through said opening may pass into said washpipe, (3) a first check valve within said washpipe adjacent the lower end thereof, said first check valve adapted to permit flow into the lower end of said washpipe from below and prevent downward flow from said washpipe, (4) a second check valve above said washpipe and in communication therewith, said second check valve adapted to permit flow upward through said second check valve and prevent flow downward through said second check valve, (5) a load tubing string above said second check valve and in communication therewith comprised of a sufficient length of tubing to retain the sand to be removed from the borehole, (6) a hydrostatic valve above said load tubing string and in communication therewith, means for opening said hydrostatic valve responsive to the force resulting from weighted contact of the lower end of said apparatus with the said accumulation in the borehole, (7) a dry string of tubing connected to said hydrostatic valve and extending upward therefrom, and (8) means for downhole detachment of said liner from the remainder of said apparatus.

2. The apparatus of claim 1 wherein at least one sec- 7 tion of tubing is provided between the upper end of said washpipe and said second check valve.

3. The apparatus of claim 1 wherein the lower end of said liner is provided with a push down shoe having a substantially cylindrical body and an open lower end, the lower edge thereof lying in a plane having an angular relationship with the axis of said cylindrical body of other than 90 degrees.

4. The apparatus of claim 1 wherein a drain sub section is provided above said load tubing string but below said hydrostatic valve.

'5. The apparatus of claim 1 wherein said first check valve comprises a hinged lid opening into said washpipe.

6. The apparatus of claim 1 wherein said second check valve comprises a ball and seat valve arrangement.

References Cited UNITED STATES PATENTS 9/ 1945 Hartsell 166163 X 4/1952 Dornacher 166--l68 l/1953 Maxwell et al. 166-163 X US. Cl. X.R. 

